[ruby-core:33541] Re: [Ruby 1.9-Feature#4085][Open] Refinements and nested methods

Hi,

2010/12/2 Loren Segal <[e-mail]>:
>> Could you tell me why
>>
>> refine Foo
>> def bar; end
>> end
>>
>> is good but
>>
>> refine Foo do
>> def bar; end
>> end
>>
>> is not so good?
>
> The "refine do ... end" block implies a method call which therefore becomes
> easily overridable at run time. This means the compiler cannot statically
> compute refinements unless it just assumed "refine" was never overridden. If
> refinements are truly meant to be lexically scoped, this should be reflected
> in the compiler's handling of them. Charles Nutter's post illustrates why
> this might matter.

Even if using is a keyword, the compiler cannot compute refinements because
refinements are defined at run-time.
The compiler can only know whether refinements are active or not.
However, it may be important for localizing the performance hit to
only scopes where refinements are active, as Charles says.

If the overhead of this check is enough small to apply for every
method invocation, there is no need to make using a keyword.

-- 
Shugo Maeda